Architosh Staff (info@architosh.com)

9 Apr 2001

Mac OS X: Core Technologies Overview -3

Continued from:

In this series will be be detailing Mac OS X from a "system overview" perspective. Many readers have never had the chance to fully delve into Mac OS X's technical background beyond the material posted at Apple.com.

Quartz and Printing

Mac OS X has a completely new graphics technology called Quartz. Many longtime Mac users understand that QuickDraw has long been the graphics technology behind the classic Mac OS. QuickDraw isn't completely dead yet however.

Quartz is special in that it is based on Adobe's PDF and PostScript technologies— the standards in the publishing world. No other current OS has this intrinsic advantage, including any version of Windows. An example of this advantage is that any OS X application which can print can save to a PDF file format, enabling users of various applications the ability to share data with users anywhere around the world, regardless of platform. PDF is the lingua franca of the Internet.

Core Graphics Services

Quartz has two key components, one of which is the Core Graphics Services, a window server for the system. CGS provides the system its ability to window and handles all event-routing (mouse clicks, etc.). CGS does not render anything itself.

Some of the advanced features of CGS include: remote display, layered compositing and buffered windows (which allows windows to repair themselves automatically and quickly).

Core Graphics Rendering

This is the second component of Quartz and is the graphics rendering library for 2D shapes. It is a rendering library "client" of Core Graphics Services (the window server). QuickDraw, the legacy graphics library, is also a "client" of CGS.

CGR uses PDF internally as its model for vector graphics. Advantages to PDF beyond its market share influences and lingua franca "status" include: good color management, internal compression and font independence.

Relative to CAD and the 3D world, Core Graphics Rendering is both precise and flexible due to its use of a floating-point based coordinate system. CGR enables a number of important distinguishing features in OS X:

• automatic PDF generation and SaveAs PDF
• automatic onscreen preview of graphics (in PDF data)
• conversion of PDF data to printer "raster data" or PostScript
• high-quality screen rendering and compositing

Printing

Printing in OS X is a large topic but relative to Quartz we can talk about a few items here. One of the most significant is the new ability of Mac OS X to allow applications to draw in "virtual pages" and map those pages to "physical pages" at print time.

This process apparently gives the OS an independence from the printing devices, something that came up in the OS X and VectorWorks interview with Nemetschek CTO, Sean Flaherty.

Additionally, a new aspect to printing in OS X will be the elimination of the classic Chooser in lieu of the Printer Center. The Print Center allows the user to find printers, submit print jobs and manage printer queues, all in one place.

The link below will work when the next installment is done.

Next: Overview - 4